We are a nation, it seems, with its eye on the main chance to rip off our employer, the taxman, or each other.

Accountants KPMG said this week that fraud prosecutions rose threefold in 1999-2004.

According to the company's fraud barometer, a measure of big cases to hit UK courts, the value of those cases was £330m.

But not everything gets to court. BDO Stoy Hayward's estimate of reported fraud comes to £643m, while the Home Office estimates the impact of fraud on the UK economy is an eye-watering £40bn.

"We've got to change the perception of fraud as a victimless crime," says Chief Superintendent Ken Farrow, head of economic crime for the City of London Police.

"The insurance industry says about 3.7% of all insurance premiums in the country is lost to fraud, and we're all paying for that, in every household, on every product we buy, in interest rates we pay, on the insurance we take out."

There was Joyti De-Laurey, the PA in a London investment bank who forged her bosses' signatures on cheques to steal £4.3m. She was sent to jail in April 2004.

Then there was Wing Kit Chu, who was convicted last week of stealing £9.2m from engineering firm Charter to fund a gambling addiction.

The money did not show up in the firm's accounts until after he resigned and eventually confessed - he was one of its foreign exchange managers, and put through fake transfers under colleagues' names.

Then there are the "businessmen" who have been caught by HM Customs' crackdown on VAT fraud - in particular a scam involving importing goods from within the EU and then absconding with the VAT.

Push and pull

"It's down to the tone from the top of an organisation," says Alex Plavsic, head of fraud investigation services at KPMG in London.

Wing Kit Chu's £9.2m fraud was only discovered when he resigned

"Do management practise what they preach in expenses, spending, probity? If they don't, people lower down can be aggrieved and may either commit fraud, or let others commit it."

If an organisation over-stresses success at all costs, that can provide the incentive to fiddle the figures, he warns.

Then there is pressure: debt, family worries and a range of other problems can start someone thinking that the gains justify the risk.

"They may think: if I get away with it, great," says Mr Farrow. "If not, well, what are they going to do? They'll probably just sack me."

Culprits

Chu and de-Laurey were both on the inside in positions of trust, which they exploited.

But neither was particularly senior, and too often in corporate fraud it's top-level executives who are taking advantage.

Fraud goes all the way from the bottom to the top

Ken Farrow, Ch Supt, City of London Police

"We've had 22 cases on the books in 2004 of acute insider involvement, and they've all involved six-figure sums," says Mr Farrow. "It goes all the way from the bottom to the top."

The worrying development, however, is that it's not just an inside job any more.

Crooks can bribe an employee, blackmail a vulnerable one, or threaten family members. Increasingly, they get people employed by target firms, burrowing deep inside before starting the scam.

"Once people are in situ in a large financial organisation, they are sometimes pressured by gangs within their communities to give up information or to assist," says Alex Plavsic.

As for public-sector fiddles - whether it is VAT fraud or ripping off the benefit system - organised crime has a huge presence, enabling the mass-production of false identities or the creation of strings of front companies.

Where next?

It all looks rather bleak.

But there are a lot of people working to correct the situation.

Fear of being caught may not be strong enough, experts believe

Financial firms are spending more and more on anti-fraud systems and people.

The government is working to rewrite the law to make prosecution easier.

There is always an upside for the economy: preventing and countering fraud is big business these days.

Armies of accountants and lawyers are there to pore over the books. If they cannot stop the next Wing Kit Chu, at least they might be able to get the money back.

This is the first in a short series on fraud in the UK. Next: Who's fighting the fraudsters - and how?